One of the mysteries of Boston Cream pie is that it is not actually a pie at all, but a cake. And what a cake, characterized by light layers of cake sandwiched with rich vanilla custard and a thick chocolate topping. The olive oil and high quality chocolate gives these doughnuts a flavor that is unlike anything you’ve ever purchased at a commercial doughnut shop!
First, make the filling, as it will need to chill for a while before you can pipe it into the doughnuts.
In a medium saucepan over medium-high heat, combine the olive oil, milk, and cream. Bring to a simmer, then remove from heat.
In a medium bowl, whisk the sugar, cornstarch, eggs, and vanilla, beating until the mixture is light yellow and form ribbons when you lift the whisk, about five minutes by hand.
Slowly pour the milk mixture into the egg mixture, whisking until completely combined.
Pour the mixture into a medium-sized saucepan (it can be the same one you started with, washed out) and place over medium-low heat. Cook, whisking constantly to keep the eggs from scrambling, until the mixture begins bubbling; continue whisking until the mixture has thickened to the consistency of a pudding. This process can take up to 15 minutes. If any bits of egg have cooked, forming lumps, strain the mixture through a mesh sieve before proceeding to the next step.
Transfer the cream filling to a bowl and press plastic wrap directly onto the surface of the custard, to keep a skin from forming. Refrigerate for 2 hours, or until completely chilled. It’s fine to make the custard a day ahead.
Now, it’s time to make the doughnuts. Place the flour, yeast, and salt in the bowl of a stand mixer. Set aside
In a medium saucepan, warm the milk, sugar, and olive oil until the mixture reaches about 105°F. Remove from heat and whisk in the eggs.
Add the wet mixture to the dry, and using the paddle attachment, mix on low speed until the dough comes together. Increase the speed to medium-high, and continue mixing until the dough is smooth and pulls away from the sides of the bowl, five to seven minutes. It will still be somewhat sticky.
Form the dough into a ball and place in an oiled bowl. Cover with a towel and let it rise in a warm place for about an hour, or until doubled in size.
Near the end of the rising period, prepare your work area. Dust a work surface with flour, and place the dough on top. Using a floured rolling pin, roll the dough to about ¼ inch thick. Using a 2- or 3-inch round cutter (or even a floured drinking glass rim, or the top of a wide mouth mason jar top, as I did), cut out as many circles as you can and place on a lightly floured baking sheet. Re-roll the scraps and continue cutting out circles until you've used all the dough. Cover the rounds with plastic wrap and again let them rise, this time for about 30 minutes.
Place paper towels under a wire rack. Have it near your frying surface. This is where you'll put the doughnuts to cool off.
It's time to get frying. Heat your oil in a large deep skillet or deep pan until it has reached 350°F. Transfer the rounds a couple at a time (you don't want them crowded) and fry until browned—about 1 to 2 minutes. Flip, and remember the second side takes less time to fry. Using a slotted spoon, transfer to the wire rack. Continue frying until you've finished them all.
By the time you're done frying, the first of the fried doughnuts should be cool enough to handle. Using a chopstick or small knife, make a hole and slightly "shimmy" it without enlarging the hole too much, to make more space in the doughnut for the filling.
Load up a piping bag with your pastry cream, and pipe as much as will possibly fit in each doughnut. (You can also spoon it in if you prefer, slicing the doughnut in half and putting a layer of frosting inside, then sandwiching it. Pipe the sides to make it look pretty.) Once filled, place the doughnuts back on the wire rack.
Finally, make the topping. In the top of a double boiler, melt the chocolate. Once melted, remove from heat and stir in the olive oil until the mixture is silky and smooth.
Spoon some of the chocolate mixture on top of each doughnut, and gently spread with the back of the spoon. The topping will still be sticky, but the doughnuts are ready to be consumed now. These doughnuts taste best the same day made. The cream filling can be made a day ahead.
Servings 24